The Shokaku class was, in my opinion the most advanced class of carriers to see service in WW II and, was possibly the best ever. This pair of ships were laid down shortly after Hiryu was commishioned (notice a trend-Kaga commishioned-Soryu and Hiryu laid down--Hiryu commishioned-Shokaku class laid down--Zuikaku commishioned-Taiho laid down--Taiho commishioned--Unryu class fails). Anyway, these were bigger than an Essex and faster than a Yorktown. Their huge aircraft capicity meant that they were nearly invincible attackers. However their underwater protection left something to be desired. Shokaku was commishioned in late 1940 and saw service in the IJN 3rd carrier division. Zuikaku was brand spanking new at Peral Harbor, and was the last big carrier present in the Phillipenes. Both ships were lost in late 1944 to numericaly superior American forces.

Aircraft: 72 (84 maximum)
Concept/Program: The third pair of fleet carriers, and the last big carriers completed before WWII. They were an improved and enlarged Soryu.

Design: In general similar to the Soryu design, but more significantly larger, more heavily built, better armed and armored. They were the best Japanese carriers built. The original design had included a port-side island on one ship (as in the previous carrier pairs), but completed with starboard-side islands.